The conformational control inhibitor of tyrosine kinases DCC-2036 is effective for imatinib-resistant cells expressing T674I FIP1L1-PDGFRα.

Shen Y, Shi X, Pan J - PLoS ONE (2013)

Bottom Line:
This study evaluated the effect of DCC-2036 on FIP1L1-PDGFRα-positive cells, including the wild type (WT) and the T674I mutant.We found that DCC-2036 decreased the phosphorylated levels of PDGFRα and its downstream targets without apparent effects on total protein levels.DCC-2036 may be a potential compound to treat imatinib-resistant HES.

ABSTRACTThe cells expressing the T674I point mutant of FIP1-like-1-platelet-derived growth factor receptor alpha (FIP1L1-PDGFRα) in hypereosinophilics syndrome (HES) are resistant to imatinib and some second-generation tyrosine kinase inhibitors (TKIs). There is a desperate need to develop therapy to combat this acquired drug resistance. DCC-2036 has been synthesized as a third-generation TKI to combat especially the Bcr-Abl T315I mutant in chronic myeloid leukemia. This study evaluated the effect of DCC-2036 on FIP1L1-PDGFRα-positive cells, including the wild type (WT) and the T674I mutant. The in vitro effects of DCC-2036 on the PDGFRα signal pathways, proliferation, cell cycling and apoptosis of FIP1L1-PDGFRα-positive cells were investigated, and a nude mouse xenograft model was employed to assess the in vivo antitumor activity. We found that DCC-2036 decreased the phosphorylated levels of PDGFRα and its downstream targets without apparent effects on total protein levels. DCC-2036 inhibited proliferation, and induced apoptosis with MEK-dependent up-regulation of the pro-apoptotic protein Bim in FIP1L1-PDGFRα-positive cells. DCC-2036 also exhibited in vivo antineoplastic activity against cells with T674I FIP1L1-PDGFRα. In summary, FIP1L1-PDGFRα-positive cells are sensitive to DCC-2036 regardless of their sensitivity to imatinib. DCC-2036 may be a potential compound to treat imatinib-resistant HES.

pone-0073059-g005: DCC-2036 induces apoptosis of FIP1L1-PDGFRα-expressing cells with Western blotting assay.A, immunoblotting of PARP cleavage and caspase-3 activation was shown in EOL-1 cells and BaF3 cells in a concentration- and time-dependent manner. B, Impact of DCC-2036 on apoptosis-related proteins. EOL-1 cells, BaF3-WT and BaF3-T674I cells were exposed to a fixed concentration of DCC-2036 (6 nM for EOL-1 cells, 400 nM for BaF3 cells) for indicated durations and then levels of apoptosis-related proteins were detected by Western blotting. C, the cytosolic AIF and cytochrome c were detected in EOL cells (6 nM) and BaF3 cells (400 nM) in a time- dependent manner by immunoblotting.

pone-0073059-g005: DCC-2036 induces apoptosis of FIP1L1-PDGFRα-expressing cells with Western blotting assay.A, immunoblotting of PARP cleavage and caspase-3 activation was shown in EOL-1 cells and BaF3 cells in a concentration- and time-dependent manner. B, Impact of DCC-2036 on apoptosis-related proteins. EOL-1 cells, BaF3-WT and BaF3-T674I cells were exposed to a fixed concentration of DCC-2036 (6 nM for EOL-1 cells, 400 nM for BaF3 cells) for indicated durations and then levels of apoptosis-related proteins were detected by Western blotting. C, the cytosolic AIF and cytochrome c were detected in EOL cells (6 nM) and BaF3 cells (400 nM) in a time- dependent manner by immunoblotting.

Bottom Line:
This study evaluated the effect of DCC-2036 on FIP1L1-PDGFRα-positive cells, including the wild type (WT) and the T674I mutant.We found that DCC-2036 decreased the phosphorylated levels of PDGFRα and its downstream targets without apparent effects on total protein levels.DCC-2036 may be a potential compound to treat imatinib-resistant HES.

ABSTRACTThe cells expressing the T674I point mutant of FIP1-like-1-platelet-derived growth factor receptor alpha (FIP1L1-PDGFRα) in hypereosinophilics syndrome (HES) are resistant to imatinib and some second-generation tyrosine kinase inhibitors (TKIs). There is a desperate need to develop therapy to combat this acquired drug resistance. DCC-2036 has been synthesized as a third-generation TKI to combat especially the Bcr-Abl T315I mutant in chronic myeloid leukemia. This study evaluated the effect of DCC-2036 on FIP1L1-PDGFRα-positive cells, including the wild type (WT) and the T674I mutant. The in vitro effects of DCC-2036 on the PDGFRα signal pathways, proliferation, cell cycling and apoptosis of FIP1L1-PDGFRα-positive cells were investigated, and a nude mouse xenograft model was employed to assess the in vivo antitumor activity. We found that DCC-2036 decreased the phosphorylated levels of PDGFRα and its downstream targets without apparent effects on total protein levels. DCC-2036 inhibited proliferation, and induced apoptosis with MEK-dependent up-regulation of the pro-apoptotic protein Bim in FIP1L1-PDGFRα-positive cells. DCC-2036 also exhibited in vivo antineoplastic activity against cells with T674I FIP1L1-PDGFRα. In summary, FIP1L1-PDGFRα-positive cells are sensitive to DCC-2036 regardless of their sensitivity to imatinib. DCC-2036 may be a potential compound to treat imatinib-resistant HES.